1. Technical Field
The present disclosure relates to a loudspeaker magnetic circuit used for various types of acoustic equipment, video equipment, and information communications equipment, including in-car use, and also relates to a loudspeaker using the same.
2. Background Art
Hereinafter, a conventional loudspeaker magnetic circuit is described with reference to the drawings. FIG. 9 is a sectional view of conventional loudspeaker magnetic circuit 4. In magnetic circuit 4, magnet 1 of ferritic material is sandwiched between upper plate 2 and lower plate 3. Magnet 1 is produced by sintering a magnetic material. Lower plate 3 is formed in a manner that a metallic plate is processed by a multistage former method. Center pole 3A is formed in the center of lower plate 3.
Magnetic gap 5 is formed between upper plate 2 and center pole 3A. A voice coil is inserted into magnetic circuit 4 and vibrates in the vertical direction by magnetic force. Therefore, the width of magnetic gap 5 has to be determined with extremely high accuracy.